hi this is Matt Baker one of the things that this channel is best known for is its family trees well today I'm going to show you the ultimate family tree the one that connects every single living thing on our planet The evolutionary tree of life if you want to get a copy just head over to our website useful charts.com or click the link in the description or pinned comment at the very bottom of this chart is Luca which stands for last Universal common ancestor this is the single celled organism from which both bacteria and ARA evolved as well as all other living things on the planet now as to where Luca and its ancestors came from well that is a question that falls outside of the theory of evolution and therefore I won't be addressing it in this video however this doesn't mean that scientists have absolutely no clue about how the first living cells arose from non-living matter there are actually several theories out there and if you're interested in learning about them just do a search for the term a biogenesis I should also point out that I've put viruses over here unconnected to the main tree that's because we're still not sure exactly how viruses are related to life they may represent a stage before the emergence of life or they might be the result of some DNA or RNA escaping from a living cell either way the main difference between anything living and a virus is that life can reproduce on its own whereas a virus needs a living host in order to replicate nowadays viruses are categorized into Realms of which three are shown on this chart Duplo DNA viira includes viruses that are based on a double strand of DNA hence dup flow these include the viruses that cause herpes mono and chickenpox VAR DNA viira includes various DNA based viruses such as the virus that caused small poox as well as the closely related monkey pox however most viruses that you're likely to be familiar with fall under ribbo viira because they are dependent on RNA rather than DNA this includes the viruses that cause the common cold as well as those that cause the flu which is short for influenza take note that there is in fact a difference between a cold and a flu a flu being the more serious of the two but of course more serious than both a cold or a flu is covid which is caused by a Corona virus Corona viruses fall under the Nido virales category finally take note that the riboa also includes the viruses that cause me measel mumps and rabies as well as HIV okay we're now ready to move up from Luca to the earliest branches of Life 10 years ago when I first made an evolution chart it was thought that life initially went in three directions which is why the previous version had three domains bacteria eukarion and ARA however nowadays the leading theory is that there should be only two domains bacteria and ARA with ukar evolving out of ARA let's look at bacteria first bacteria is the type of single- celled life that we're most familiar with because like viruses they cause a lot of diseases take for example streptococus which causes both strep throat and pneumonia or stafilic cacus which people often get in wounds both of these bacteria belong to the basela philm an even larger bacteria film is pseudo monod DOA it includes the germs that cause ecoli cha salmona menitis and worst of all the Bubonic plague aka the Black Death the most deadly pandemic in all of human history but not all bacteria is bad there's also good bacteria called probiotics such as lactobacilus which is used to make yogurt and is good for our digestive systems there's also py bacteria pus being Greek for of the sea these bacteria live in the ocean and are super important for the Earth's overall ecosystem ARA are far less familiar to the average person they were initially lumped together with bacteria but are now understood to be quite distinct in fact they include some of the most extreme forms of single cell life such as those that live in super hot environments called thermopiles and those that live in super salty environments called hallof files however ARA also includes a proposed Super film called Asgard named after the home of the Gods in Norse mythology it's from Asgard cells that the very first ukar cell is thought to have developed around 2 billion years ago now UK carot cells differ from bacteria and archa cells in that they are much larger and more complex being comprised of many different parts most notably a nucleus which is where the cells DNA is located this contrasts with bacteria and archia cells which have DNA floating around in the middle another part of a ukar cell that you might be familiar with are the mitochondria which are kind of like little energy factories interestingly these came to exist within ukar cells via a process called endosymbiosis basically a bacteria cell similar to those py bacteria I mentioned earlier went inside an Asgard cell to create a sort of supercell one example of these early type of supercells are amibas however over time these new kind of cells started to join together to form multi-celled organisms as well such as brown algae which is now placed in the S supergroup but then there was yet another endosymbiosis event around 1 billion years ago this time a type of cyano bacteria and entered a eukarion cell to create arip plastids which have yet another special cell part called plastids the most famous type of plastid is the chloroplast which is used by plants to convert energy from the Sun into a type of energy that can be transferred to other living things as humans all of the energy that we have comes from eating plants or from eating animals that eat plants or in rare cases from eating animals that eat animals that eat plants plants take note that some types of brown algae did not originally have Plastics but perhaps inherited them from Red LGA now take note that all of these early ukar life forms exist outside of the three main kingdoms which are plants fungi and animals at one time these early ukar were placed in a fourth Kingdom called protests and then later they were divided into a bunch of smaller kingdoms but nowadays the exact classification has been left up in the air because scientists are still trying to figure out exactly how everything pieces together another big thing that has only been discovered quite recently is that fungi are actually more closely related to animals than they are to plants this is because both fungi and animals evolved around a billion years ago from early opis whereas plants did not the term aiston comes from a combination of Greek words that means something like rear pole that's because simple aiston have these sort of tail-like things called flagellum now for the rest of this episode as well as episodes 2 and three I'll be focusing entirely on the animal Branch however take note that in episode 4 I will be coming back to talk about both plants and fungi so stay tuned for that anyhow the earliest types of animals probably looked something like sea sponges which to be honest don't really seem like animals even though they are you see despite the fact that sea sponges don't move they are in fact animals because they have animal cells just like you and me corals which belong to the same filum as jellyfish also don't move but they at least have a very simple nervous system and it is the nervous system that eventually allowed animals to evolve the ability to move react and eventually to think but I'm getting ahead of myself the other big thing that developed early on in the animal branch is bilateral symmetry you only have to look in the mirror to understand what this is it's the reason why you have two eyes two ears two arms two legs Etc basically if you draw a line down the center of your body or that of most animals you get two sides that mirror each other with the emergence of bacteria animals went in two very different directions there's the protone branch and the dorone branch these two terms mean mouth first and mouth second referring to the different ways that animal embryos can develop most animals have a digestive system with a mouth on one end and an exit hole on the other protostomes develop the mouth first and then the exit hole whereas deuterostomes do the opposite the other big difference is that the protone branch went on to produce life forms with an exoskeleton or outer shell like insects for example whereas deuteros does went on to produce life forms with an endoskeleton meaning that they have their hard Parts called Bones on the inside let's look at protostomes first the earliest types of protostomes were the ones that don't have exoskeletons such as flatworms and earthworms but then came Mullis which do such as snails and clams the most interesting type of mollusks are the seop pods which include squid and octopuses their ancestors would have had shells too but at some point they lost them however they gain something potentially better eyes very similar to our own which is a great example of something called convergent evolution these are instances where similar structures evolved independently of each other on different branches of the tree octopuses in particular are also among the most intelligent non-human animal animal on the planet which just goes to show that there's no one branch on the tree that is necessarily more advanced than any other now while I'm here I'll point out the fact that most living things can be categorized according to the very old naming system developed by Swedish biologist Carl lenus back in the 1700s lenus is the one who developed the ranking system that starts with Kingdom and then proceeds through film class order family genus and species so to make things clear many species make up a Genus many jera make up a family many families make up an order many orders make up a class many classes make up a filum and many F make up a kingdom now since the 1700s it's become clear that things are actually more complicated and that's why there are often other category names inserted between the main ones such as bateria and and protostomia in these cases those divisions are simply called a clade okay next I want to start back at the protest node and proceed up this time towards the insects but first I want to point out this event here the Cambrian explosion which occurred around 540 million years ago you see this is the point in which animal life started to go in a bunch of different directions as evidenced by the wide variety of fossils that can be found after this point however it's important to remember that creatures with bones or shells leave better fossils so it might just be that 540 million years ago was when shells and Bones became more common regardless it was around this time that the first taop pods evolved taop pod meaning organized feet this category includes tardy grades which look like tiny bears wearing hazmat suits but more importantly it includes the massive arthropoda philm which has all the spiders insects and other creepy crawly things these were the very first animals to leave the water and crawl onto land although obviously some like crabs and lobsters still live in the seat the very first arthropods would have looked something like this kind of like a milliped note that it has a segmented body and lots of legs all modern arthropods have the same basic body plan but with modifications for example insects evolve to have only six remaining legs however another six of their former legs evolved to serve as mouth Parts in addition to this most of these segments fused over time so that insects are now left with only three the head thorax and abdomen contrast this with spiders who as you probably know have eight legs and only two segments but what you probably didn't know is that most of their legs evolv from the same appendages that now serve as mouth Parts in insects spiders two mouth parts or fangs actually evolved from what used to be their antenni and two of their former legs evolved to become pincers which are much larger on the closely related scorpions another thing to note is that crabs are actually more closely related to Insects being that both of these groups evolved from early crustations insects have however fall under the category of hexapods because like I said they all have six legs some insects also developed Wings early on such as dragonflies but regardless of whether an insect crawls or flies technically speaking most insects are not bugs although the word bug is used casually to refer to any creepy crawly thing from a scientific point of view only those insects belonging to the hmip order are are true bugs the largest category of insects is actually the holometabola superorder these are insects such as beetles and butterflies that go through a metamorphosis involving four stages egg larva Pupa and adult included in this group is the hopera order which includes both ants and bees arguably some of the most intelligent insects due to their complex social structures okay let's now go all the way back down to bateria and follow the durostone branch instead however the most important durostone film is Cordata Cordata includes lancelets as well as all the vertebrates which are animals with backbones protecting a column of nerves that run down the back the earliest vertebrates would have looked similar to lampra which have a mouthful of teeth but no jaw now once the jaw evolved things went in two directions on the one hand we get fish with skeletons primarily composed of cartilage like sharks and rays and on the other we get fish with skeletons primarily made of Bones which are much harder if we follow this bony fish line we'll see that things once again split in two we get rayin fish and lobe finned fish the vast majority of fish that you're likely familiar with are rayin meaning that they have simple fins like this that flap helping the fish to swim in the water all Rin fish belong to the atino taji class which contains about 50% of all known vertebrate species most of these in turn are teleosts which can then be broken down into two main clayes the osila and the oste osila includes catfish sardines tetras and carp with the carp order being the one that goldfish and koi belong to as well as minnows whereas oste includes Cod salmon and the percomorphs percomorphs are evolutionary speaking newer fish in that they mostly developed after the extinction of the dinosaurs they include edible fish like tuna halet and perch but also popular aquarium fish like Guppies cichlids and betas and then there's one of the strangest fish of all seahorses named because they have upright heads that look like horses let me now tell you about lob finned fishes although far less common they are super important in that it is from the lobed finfish or sarop rigi that all land vertebrates descend so as you you can see from this diagram lob fins are more complex than Ray fins they have bones that look more like little limbs which is basically what they are although LED finfish just use them to Flap and hence swim this would later allow certain creatures to do a bit of crawling in shallow water as well the main lob finned fish that are still around today are the cants and the lungfish okay so the first thing we need to discuss is how a creature like this eventually evolved into a creature like this both have skulls and a central backbone so that's not the issue the issue is how a fish's fins which are used for swimming evolved into a land animal's limbs which are used for walking well like I said last time it has to do with a special category of fish called sarop toi which still exist to this day but are quite a bit different from the dominant atino terigi class you see most fish have rafin that look like this they're basically just one strong bone with a bunch of really thin bones attached to it forming a sort of fan that flaps back and forth in contrast copter ridy fish have fins that look like this they too have a bunch of thin bones albe it a bit thicker but what's really interesting are these three bones here if you were to look at an x-ray of your own arm you'd see that the upper part between your shoulder and elbow has a single bone which is called the humoris whereas the lower part between your elbow and your hand has two bones called the radius andna after that you get all the small bones in your wrist hand and fingers well this basic structure can be found in just about every four limbed animal on earth whether whether it's a lizard or a lion even birds have it as well as bats and whales that's because all four limbed animals are the descendants of sopter rigi fish but how did some fish go from having th Rays to having lobe Rays well it may be easier than you think if you've ever had a home aquarium you might be familiar with zebra fish they're often used in scientific research and nowadays you can buy a genetically modified version called glof fish which glows in the dark but just a few years ago in 2021 scientists were able to genetically modify a zebra fish in another interesting Way by creating a mutation in just one gene called haxa 11 they were able to breed Zer fish with two new fin bones similar to the radius andna however stronger limbs were not the only thing that were needed in order to make the transition from water to land possible there was also the issue of breathing as you probably know most fish breathe using gills which are organs behind the eyes used to extract oxygen from water well it might surprise you to learn that lungs actually evolved around the same time as gills in other words the earliest fish had both however most fish ended up relying entirely on their gills which then allowed their lung to evolve into the swimbladder which they could then use to control their buoyancy but notice that I said most fish one of the surviving members of the copter RI branch is the lungfish which as its name implies uses lungs to breathe but even if some fish had lungs as well as stronger limbs what led them to leave the water and crawl onto land well it wasn't a sudden move like most cartoons suggest like most things in evolution it took millions of years first of all it's important to remember that vertebrates were not the first animals to leave the water insects beat them onto the land by tens of millions of years and plants and fungi were there even earlier which is good because once the vertebrates arrived they needed something to eat and eating is one explanation for why some fish eventually ventured into shallow water and then into shallower water and then even more shallower water and so forth you see one of the great things about shallow water from a fish's perspective is that it has less Predators so once there were ample insects to eat there I mean why wouldn't a fish move into that neighborhood now I've taken a little longer to explain this part of the tree because it's often the part that some people find hard to accept in the past creationists like to talk a lot about missing links and how no one had ever found a fish with feet well that's no longer an argument they use because in recent decades we've actually found fossils that look exactly like a half fish half lizard-like creature the most famous of these is tiic discovered in 2004 living around 370 million years ago it had scales and gills like a fish but also a flat head and Strong downward-facing Limbs like a lizard note in particular that it had four limbs this is important because every single vertebrate after this point also only has four limbs which is why they are called tetrapods the earliest tetrapods such as icha would have been amphibious meaning that they could live both in water and on land some tetr pods still can and these are placed in the amphibian class the two most well-known groups being salamanders and frogs take note that a toad is just a special type of frog with drier skin and shorter back legs all non- amibian tetr pods are amniotes this is because they evolve to have an extra layer that surrounds their embryos forming What's called the amniotic sac evolving around 320 million years ago this served to better protect the embryo and hence it allowed certain tetr pods to lay eggs on land instead of in the water like frogs and salamanders still too the end result was that amniotes were able to venture further and further away from the water at this point tetrapods split in two very different directions we get the synapsid line which eventually led to mammals and the copid line which leads to reptiles and birds for the rest of this video we are going to focus exclusively on the ssids returning to the synapsids in episode 3 first of all take note that the word copid literally means lizard face even though not all reptiles are actually lizards lizards are actually just one type of reptile but because they are the most common type around today people sometimes use the two terms interchangeably all lizards such as geckos dragon lizards chameleons and iguanas belong to the squamata order as do snakes snakes are included because they actually evolved from earlier lizards that went on to lose their legs another major reptile order that still exists today is the test Udin order which includes Turtles and tortoises the difference between a turtle and a tortoise is kind of the same as the difference between a frog and a toad turtles live in more wet environments whereas tortoises are just a special type of turtle that live in more dry environments finally in terms of major extant reptiles there's the crocodile order which also includes alligators the easiest way to tell the difference between a crocodile and an alligator is to look at their nose although you obviously don't want to get too close crocodiles have a more pointy nose like a V whereas alligators have a more Roundy nose like a u note that crocodiles belong to a subgroup of reptiles called archosaurs which means that they are more closely related to dinosaurs than either lizards or Turtles now before I move on to talk about dinosaurs let me point out three orders that are often associated with dinosaurs but were not actually true dinosaurs in the technical sense these include parasaurs such as pterodactyls which most people tend to think of as flying dinosaurs as well as iosaur and plesiosaurs which most people think of as swimming dinosaurs note that iosaur looked more like dolphins whereas plesiosaurs looked more like the supposed Loch Ness monster actual dinosaurs are only those reptiles that belong to the dinosaur clay which evolved from early archosaurs as you might know the word dinosaur literally means terrible lizard it was coined in 1842 around the same time that the very first partial dinosaur skeletons were found and preserved now humans around the world had been finding individual dinosaur bones for centuries before this but it wasn't until the mid 1800s that geologists started to realize that they belong to an extinct form of large reptiles prior to this it was assumed that they must have belonged to giant humans or dragons nowadays we know that dinosaurs lived approximately 240 years ago and can be divided into two main categories orysia meaning bird hipped and sisia meaning reptile hipped this is somewhat confusing because Birds eventually evolved from sisia anyhow orian dinosaurs were mostly Plante eating and they include well-known Genera like anosa surus Parasaurolophus stegosaurus and Triceratops in contrast sisan dinosaurs include both Plante eaters called sorop pods as well as carnivores called theropods sorop pods like the familiar brontosaurus are those really big dinosaurs with long necks in fact they were the largest animals to ever walk the earth however it's the theropod s such as Tyrannosaurus rex that we tend to consider to be the mightiest of all the dinosaurs which is interesting because it's from the theropod dinosaurs that birds descend the path to birds starts with Avi which simply means bird wings this CLA includes Arch opter which is the earliest known dinosaur to have feathers and wings remember pterodactyls are not true dinosaurs and their line died out Arch opter is therefore also considered to have been the first bird even though technically it does not belong to the AV or bird class now this is where I have to point out an anomaly on this chart as I mentioned last time living things are still classified using the old lenan naming system which works like this inside a kingdom are many Fila inside a philm are many classes inside a class are many orders and so on there's never supposed to be a film within a filum or a class inside a class but in this case we do have a class within a class we have the av's class nested inside the reptile class this is because when lenus made the original system he didn't know that birds were descended from reptiles he thought they were a totally separate category and therefore he classified them as such but we now know that Birds definitely descend from reptiles from dinosaurs to be exact so does this mean that birds are dinosaurs well technically speaking yes although in common usage we tend to reserve the word dinosaur exclusively for the now extinct non-avian dinosaurs birds are also technically reptiles but again in common usage we tend to use the word reptile only for non-avian reptiles because of this change in understanding some taxon s want to stop calling aies a class and simply consider it a general CA instead I've opted to keep it as a class because I think generally people still tend to think of birds as being distinct from other reptiles which is why they end up being a class inside a class okay when it comes to birds the oldest type cladistically speaking are ostriches and the related emu and Kiwis ostriches cannot fly but evolved from earlier birds that could next comes foul which can be divided into water foul like ducks and land foul like chickens some fowl like geese are very good at flying While others like chickens can fly only a little bit of course one of the most important things about foul is that they are a major food source for humans not only in terms of their meat but also their eggs all the remaining birds fall under the category of neoaves or new Birds to explain their origin I first need to introduce you to some of the terms used for measuring time in the Deep past which I've largely avoided up to this point in episode one I mentioned the Cambrian explosion which is so named because it occurred at the beginning of the Cambrian Period the first of 12 time periods that cover the last 540 million years give or take a million now take note that the starting date of 54 40 million years ago was chosen not because that's when life began but rather because that's when life started to go in a bunch of different directions as evidenced by the fossil record so after the Cambrian comes the ordovician silurian devonian Carboniferous perian Triassic juracic Cretaceous paleogene neogene and quaternary now throughout the history of life on Earth there have been five m major Extinction events caused by either asteroid impacts or volcanic eruptions or some other huge catastrophe in each case these events caused the majority of species living on the planet to die out completely however this in turn helped Drive Evolution because the species that did survive could suddenly take advantage of a dramatically new situation so what we find is that following each one of these major Extinction events we get what was once a small branch of the tree suddenly going in a bunch of new directions so for example after this one here that's when we suddenly got lots of different types of insects and bony fish and this one here well that's around the time that the first land vertebrates started to really Thrive but then came this one the PT Extinction it's named that because it marks the transition between the perian and Triassic periods well it was the biggest Mass extension event of all time killing off about 80% of all ocean species and about 70% of all land species in fact the PT Extinction changed things so much that we use it to Mark the transition to A Whole New Era we call the first six periods the Paleozoic Era Paleozoic meaning old life whereas we call the next three periods the mesic era meaning middle life the Paleozoic is also sometimes referred to as the age of fish because the greatest diversity of life during this entire era could be found in the ocean whereas the Mesozoic is referred to as the age of reptiles because that's when the dinosaurs dominated although true dinosaurs didn't actually appear until the Jurassic after yet another major Extinction event which brings us to the final mass extinction and the one that you're likely the most famili amiliar with most people know it as the KT Extinction K standing for Cretaceous and T standing for tertiary which was an older term used for the paleogene and neogene we know that this one was definitely caused by an asteroid and we even know exactly where it hit it's right here in Mexico but the reason most people know about it is that this was the event that killed off the dinosaurs Paving the way for mammals to dominate that's why the current ERA the cazic which means recent life is also called the age of mammals however that's a bit misleading because it could also just as accurately be called the age of birds which is the reason why I took the time to explain all of this you see it was right after the KT event and the extinction of the dinosaurs that the neoaves really took off or to put it in another way it was after the KT event that the non-avian dinosaurs were replaced by the Aven dinosaurs okay so let's now take a look at the neoaves first off there's the seabirds which include herons and Pelicans but also penguins and then there's the shore birds which include seagulls and their relatives the word Colombia comes from the Latin Columba which means a pigeon or Dove so that's why these birds are in the columbiformes order take note that there's no real difference between a pigeon and a dove besides the fact that we tend to use the word Dove for the smaller species in this group the word apodiformes literally means footless even though birds in this order such as hummingbirds do actually have feet it's just that they have rather small feet so small that they can't even use them to walk or jump all other neoaves fall into the land Birds category which could more accurately be called the tree Birds category because the defining feature of this group is that they mostly live in trees from here things split into the afro aves which originally evolved in what is now Africa and the austral aves which originally evolved in Australia and South America afro AVS includes woodpeckers most birds of prey like eagles and Hawks as well as as owls whereas australes includes parrots and the largest bird order of all the passerines or perching birds passerines are well known to most people because they include all of the song birds many of whom live alongside humans in our neighborhoods as well as in the forest these include popular backyard birds like sparrows Cardinals finches chickes starlings and Robins but it also includes a family of birds that ranks among the most intelligent animals in the world corvids corvids include mag pies and Jays as well as crows and ravens the main difference between a crow and a raven is that a raven is much larger and goes whereas a crow is smaller and goes okay last time I pointed out this circle here which represents the very first amniotes amniotes are so named because in their embryonic stage they grow inside an amniotic sac in egg L creatures this sack is located within the egg itself alongside a separate sack called the Yol which eventually gets absorbed however in livebearing creatures and humans the amniotic sac grows inside the womb and then ruptures just prior to birth which is when we say that a mother's water has broken the earliest amniotes would have all been egg layers and the first ones likely evolved around 320 million years ago but very soon after that they split into two groups each going in a very different direction this fork in the road so to speak is one of the most important on the entire tree because it basically splits the entire top into into two parts on the right side are the reptiles dinosaurs and birds which we discussed last time and on the left are the mammals which we're about to get into the technical term for these two groups are ssids and synapsids as I mentioned last time sopit literally means lizard face but what about the word synapsid well the word synapse means something like connecting Arch or Bridge therefore we could say that synapsid means means Bridge face to better understand this word choice let's take a look at some skulls this is the skull of a coote which is a synapsid notice this part here it looks like a connecting Arch or Bridge most synapsids have this feature whereas ssids as represented by this T-rex skull do not another key difference is that synapsids have only one opening behind each eye socket whereas most ssids have two now we humans are also synapsids so you can actually feel that connecting bridge on your own face it's right below your temple your temple being what's left of that single opening behind the eye socket basically this bridge connects your cheekbone to the place where your jaw begins that's why when you chew you can feel the muscles moving in this area the earliest type of synapsids such as demetron were originally called mammal likee reptiles that's because on the outside they looked like a reptile even though on the inside they were starting to develop mammal-like features later they were called pliosaurus which is the term I use on this chart but note that I put it in quotation marks that's because officially this term is no longer in use either even though in common speech it's still the name that most people use technically it's better to call creatures like demetron Proto mammals or stem mammals because even though they looked like reptiles they were not now in episode 2 I introduced this chart called the geologic time scale which divides the last 540 million years into 12 periods well pliosaurs live during these two periods here the Carboniferous and the perian but then during the perian they were replaced by a new kind of protom mamal the therapsit which included codons meaning dog teeth these creatures managed to survive the massive PT Extinction event and then really started to thrive during the early Triassic so in other words Proto mammals were around before the emergence of the dinosaurs in fact up until the mid Triassic the synapsids were the dominant land animals not the ssids it wasn't until the second half of the Triassic that the archosaurs and then later dinosaurs started to take over reaching their Peak during the Jurassic and Cretaceous and then of course came the KT Extinction in which a massive asteroid hit the earth wiping out all of the non-avian Dinosaurs the explosion would have been equal to about a billion heroshima but it wasn't just the actual impact that caused the extinctions it was the aftermath too initially there would have been radiation firestorms and tsunamis but then perhaps worst of all all that that debris thrown up in the air would have blocked the Sun for about 2 years meaning that plants couldn't perform photosynthesis but it was this event as well as the previous two Extinction events that helped Drive the evolution of mammals one theory is that once the dinosaurs became dominant the main protom mammals to survive were the smaller nocturnal ones because they were better at hiding from big predators this helps explain some of the additional changes that occurred to synapsid skulls you see another feature of later synapsid skulls is that the jaw is made up of just one large bone whereas the jaw in copid skulls is made up of several bones so what happened to those other jaw bones well we synapsid actually still have them but ours are really really tiny and located in our ears they help us to hear much better than reptiles and birds do synaps skulls also developed a secondary pallet which separates the nasal cavity from the oral cavity this allows us to smell much better than reptiles and birds do but whereas synapses have Superior hearing and smelling ssids have better Vision they have four cones in their eyes whereas we have only three and most mammals have only two this all makes sense if we consider that our synapsid ancestors were mostly nocturnal if you're moving around in the dark being able to distinguish between colors isn't really all that important but being able to hear well and smell well is another feature that Proto mammals developed was the ability to regulate their own temperature rather than simply relying on the Sun for warmth this requires a lot more energy but it paid off because warm-blooded creatures are more adaptable being able to grow faster and survive in different environments including cold nights and and deep holes underground One Way Proto mammals managed to regulate their temperature was by developing fur another was by developing the ability to secrete fluids like sweat for example which brings me to the feature for which mammals get their name mamory glands mamory glands produce milk which mothers initially used not to feed their babies but simply to keep their eggs moist Over time however it ended up being the primary food source for Mammal newborns which allowed them to stay closer to their mothers and hence away from predators now we tend to think of all modern mammals as being livebearers but there are still a few around that lay eggs such as platypuses and aidas both of which live in Australia and belong to the monot order monot meaning one whole this is a reference to the fact that they like birds and reptiles have just one hole that they use for all their bodily functions all other mammals are thean meaning beasts and they can be divided into two categories marsupial which again only live in Australia and placentals marsupial give birth to live young but in a not quite ready State once they leave the womb they crawl up into a special pouch called a marsupium where they continue to develop a little more now the marsupial that you're probably most familiar with are kangaroos but there are others still around like koalas wombats and AP possums and up until around 60,000 years ago there were many more as well some of them quite large like the Rhinos sized depron and the cat-like tholo the vast majority of mammals however are placentals meaning that they develop placentas during pregnancy which feed their young until they are fully ready to be born so no egg and no need for a pouch now in order to explain the two main branches of placentals boreo etheria and atlantogenata I need to First tell you a bit about prehistoric continents as you probably know there was once just one big super continent on Earth called Pangia it existed during the Triassic period which was right around the time that the very first mammals appeared but then during the Jurassic period it started to break up with Australia coming off first which is why the mammals there are so different eventually though the largest chunk of Pangia split into two main parts laasia in the north being comprised of what would eventually become North America Europe and Asia and gondwana in the South which was basically South America and Africa squished together so the reason why we have two main types of placentals is that the boreo uan mammals initially evolved in laasia whereas the atlanto genan mammals initially evolved in gondwana let's look at atlantogenata first it can be split further into xenarthra which developed in West gondwana and afrotheria which developed in East gondwana xenarthra means strange joints and they are so named because they have some extra parts in their spine examples include armadillos sloths and ante eaters in contrast afro theia consists of arars manatees and most notably elephants including the two main types still alive today African elephants and Asian elephants however if we were to go back just 4,000 years there would be a third kind as well mammoths for the rest of this video we'll be dealing with boreo etheria which can also be split in two first there's Loria theia which is named after that Northern supercontinent I mentioned earlier here we find hedgehogs and bats as well as all of the hooved animals called ulates these in turn can be divided into peroda Tila meaning odd Toad and Aroda Tila meaning even toad those with an odd number of toes per hoof include horses who have just one and rhinos who have three in terms of even toed ulet hippos pigs and deer all have four toes per hoof whereas the rest have two such as giraffes camels and bovids bovids being the family that includes cows sheep and goats but also included in Aroda Tila are a group of mammals with no Hooves at all at least not anymore these are the satti like dolphins and whales who now live exclusively in the water but who evolve from hippol likee ancestors who once lived on land finally within Laria theia is the carnivore order where we find Humanity's two best friends cats and dogs in fact this entire order can be split in two between the cat-like carnivores called felies and doglike carnivores called canopies in fioria we find hyenas as well as the fidi family which includes cougars cheetah Bobcats and the now extinct saber-tooth tigers and Panthers tigers lions and leopards are actually all Panthers even though we tend to reserve the word Panther only for black panthers which are actually black leopards and then of course there's the felis genus which includes the African wildcat from which the domestic cat felis ctis evolved on the doglike side are many different families such as the ones with bears skunks raccoons seals and Otter but then of course there's kenned the dog family which includes foxes coyotes and wolves it was from the gry wolf canis lupus that the domestic dog evolved okay so that takes care of Loria theia let's now look at uarco conto garies which is so named because it is made up of uarco meaning true rulers and garies which means Mouse garies has more than just mice though it includes rabbits as well as the rodents which can be divided into beavers porcupines squirrels cppy Bears rats and hamsters uar Canta includes tree shoes as well as the most important mammal order of all at least to us the primates even the word primate itself indicates its importance as it literally means of the first rank but again this is obviously from the human perspective from an evolutionary perspective no one branch of the tree is is any more important or better than any other as long as it's still there it can be considered successful and even from the perspective of our own definition of intelligence there are many branches of this tree that have produced highly intelligent life forms besides primates there's also cations elephants parrots and Corvettes and way down here there's octopuses who are known to use tools even pigs are smart than most people realize but on the other hand I don't think we have to apologize for having a particular interest in primates after all they are our closest relatives so let's take a look first I'll mention the two prian orders Tarsiers and lemur all other primates including monkeys and apes are called simeons which literally means flat noosed now a lot of people use the words monkey and ape interchangeably but but they shouldn't because these are actually two very different types of simeons monkeys are generally much smaller and have tails whereas apes are bigger and are the only mammals to lack Tails monkeys themselves can be divided into two main types based on where they first evolved so there are old world monkeys from Africa and Asia and New World monkeys mostly from South America in terms of Apes most belong to the homed family or great Apes but there's also one family of lesser apes the Gibbons the great ape family currently consists of for janira gorilla Pongo AKA orangutans pan which includes common chimpanzees and bonobos and finally homo humans as you probably know humans are most closely related to chimpanzees which is why I added an extra node here representing their last common ancestor this ancestor was neither a chimp nor a human but rather something in between that lived around 9 million years ago perhaps something like the now extinct sahelanthropus chenis discovered in 2002 what's more certain is that around 3.5 million years ago our ancestors were ostop meaning Southern Apes this now extinct genus was first discovered in 1924 but was made famous in the 1970s with the discovery of this partial skeleton nicknamed Lucy since then more complete skeletons have been found and the genus has been divided into many different species and perhaps even multiple jira now before I move on I want to shout out ET matah who produced all of the images for this part of the tree you may know his work from the Stefon Milo Channel but if you want to follow ET directly you can do so on Instagram I'll leave a link to his profile in the description eventually one of the ostop species evolved into a new genus called homo the earliest known species of which was homohabilis meaning handyman because this species is known to have used stone tools a little later came Homo erectus meaning upright man the first fossils of this species were found in Asia way back in 1891 but since then similar fossils have been found in Africa as well some researchers simply call these African specimens African Homo erectus but others consider them to be a totally different species and instead label them as homo ergaster meaning Working Man either way it is from the African hominid that all humans today descend by way of an intermediate species called homo h highle berenis but before we move forward towards Homo sapiens I want to first point out this species here homo floresiensis discovered in 2003 on the island of Flores in Indonesia this early homonid stands out because it was much smaller than all the other homo species perhaps due to Island dwarfism initially it was thought that they might still have been around as recently as 10,000 BCE but more recent estimates have pushed that back closer to 50,000 BC there are currently two main theories as to where these hobbit-sized people came from one is that they descended from Asian Homo erectus the other is that they were actually the remnants of an earlier species perhaps as old as Homo habilis but back to homo heidleberg Enis a species that lived from around 700,000 years ago to around 200,000 years ago and lived in both African and Europe and perhaps even as far away as China this species was the common ancestor of neandertals homo sapiens and denans neandertal fossils were the first fossils to be recognized as belonging to some type of prehistoric human as far back as 1856 which was 3 years before Darwin's On the Origin of Species nowadays we have 400 neandertal specimens and have completely mapped out their genome from which we now have firm evidence that neandertals and Homo sapiens interbred with each other in contrast we only learned about denin in 2010 and we currently only have around 10 specimens we have however mapped out their genome and from this we have learned that they interbred with both neandertals and Homo sapiens neander TOS are named after the neander valley in Germany where some of the very first remains were found and they are generally now seen as being a unique species called homon neander Talis however the denisovans which are named after denova cave in Russia have not yet been assigned an official name now the main difference between the Three Kingdoms boils down to how each one obtains its food animals including us humans have to eat our food meaning that we have to literally take other life forms put them in our bodies and then let our internal digestive systems do some processing similarly fungi also need to obtain their food from other sources but a fungus doesn't need to ingest its food because it has the ability to absorb it externally but plants plants are super special because they alone have the ability to make their own food through a process called photosynthesis they can do this because they have little green cell parts called chloroplasts that take energy from the Sun and turn it into sugar interestingly the word chloroplast comes from the Greek and literally means green thing that makes now back in episode 1 I explained where these little green cell parts came from they were originally a type of cyanobacteria again the word cyan comes from the Greek and refers to a sort of greenish bluish color but then around 1 billion years ago an endosymbiosis event occurred whereby that bacteria entered a larger ukar cell to create the first archip plastid from there we got a form of multicellular life called algae which comes in green red and brown algae are similar to True plants in that they can perform photosynthesis but they differ in that they're far more simple and live exclusively in the water okay so the first major split within the plant kingdom is between vascular plants and nonvascular plants vascular plants have a network of veins kind of like we animals do but whereas our veins carry blood plant veins carry water and nutrients together plant veins make up all the various features that we tend to associate with plants things like roots stems branches and leaves but not all plants have these things the those that don't I.E the nonvascular plants belong to the bopy division take note that when it comes to plants and fungi the word division is used in place of philm the type of broida that you're probably the most familiar with is moss that spongy green stuff that spreads out over surfaces but never grows very tall this is because brop phyes need to stay close to moisture since it was in water that plants originally evolved however that vascular plants do much better on land and can grow much higher thanks to their stems and branches which a provide them with structure and B help transport water up if you've ever cut a carrot you may have noticed that it has a little circle inside a bigger Circle while all plant stems and branches are similar the circle in the middle is called the xylm which in ancient Greek means wood its job is to carry water and minerals up from the ground to the top of the plant in contrast the Outer Circle is called the flum and it serves as a two-way pipe carrying sugar the byproduct of photosynthesis to every part of the plant okay the next split on the chart divides the vascular plants into those with seeds and those without seeds those without belong to the pteropid division terid meaning ferns so ferns like most other plants do have branches and leaves but since they don't have seeds they reproduce in a slightly different way if you look on the underside of a fern Leaf you'll notice a bunch of tiny little bumps these are called Sor and they are full of spores spores differ from seeds in that they are produced asexually which brings me to the whole topic of plant sex most plants produce seeds and seeds are basically little embryos meaning that in order to create one you need both a female and a male or at least a female part and a male part but before I dive into that I need to point out that seed bearing plants can be divided into two main categories angiosperms and gymnosperms angiosperms are also known as flowering plants but they could also be called fruit bearing plants because only plants with flowers produce fruit and what is fruit well fruit is simply a special container for seeds in fact the word angiosperm literally means container AER seed this is in contrast with gymnosperm which means naked seed now when it comes to gymnosperms most people tend to think only of conifers or cone bearing plants almost all of which are evergreen but there are actually a few other types of gymnosperms as well such as the Ginko tree which loses its leaves so what unites all gymnosperms is not cones or being Evergreen but the fact that their seeds aren't enclosed in Fruit let's look at the well-known pine tree as an example when I say pine cone you probably think of this but this is actually just one kind of pine cone the female kind on the same tree you'll also find these ones which are the male kind so I guess we could say that pine trees at least most species of pine are hermaphrodites meaning that they are both male and female at the same time what happens is this the male pine cone releases pollen some of which blows in the wind and enters the female pine cones where it combines with OVA to form embryos or seeds these seeds then grow and when they already the female cone releases them in a mostly naked form I.E without fruit some angiosperms such as pumpkin plants for example reproduce in a similar way except instead of cones they have flowers and instead of producing mere seeds they produce fruit with the seeds on the inside so for example on a pumpkin plant you'll find two different types of flowers although they look quite similar one type will be male and the other type will be female once the female flower is pollinated the fruit in this case the pumpkin starts to develop at the bottom of the flower over time though the flower Fades away and the Pumpkin gets bigger and bigger now there are actually two other ways that seed bearing plants can reproduce for example most willow trees are either male or female so in this case some trees produce only male flowers and others produce only female flowers but it's actually the final way that is used by most angiosperms most angiosperms produce just one type of flow but that flow is both male and female at the same time sometimes called perfect flowers they have both staman which are the male parts and carpal which are the female parts but angiosperms are not actually classified by how they reproduce in instead they are classified by how their seeds grow the two main types being monocots and dcot cot refers to cens which are plants very first leaves if you've ever tried to grow plants from seeds you've probably noticed that these Sprouts usually look something like this those two initial leaves are the cotty leens and since there are two of them we know that this plant is a dcot grass on the other hand is a monocot so when it sprouts it looks like this another good example is to think of a corn kernel versus a peanut a corn kernel is a monocot seed which is why it's just a single piece whereas a peanut is a dcot seed which is why you can split it in two most dcot are udic cots meaning true dicots but there's also magnol dicots which are some of the oldest angiosperms still around as the name suggests this group includes includes Magnolias but it also has avocado cinnamon Laurels black pepper and radiator plants which are one of the more popular types of house plants coming in lots of different varieties if you have a peperomia plant at home you'll notice that its flowers look more like long thin cones than normal flowers that's a reminder that it belongs to the oldest category of flowering plants going all the way back to when flowers were still evolving from cones let's look at monocots next this is where we find almost all of the plants that start out as bulbs like onions and garlic as well as lies and tulips but it's also where we find major tropical fruits like coconuts bananas and pineapples finally and perhaps most importantly it contains all of the grasses which include the world's three largest food crops wheat rice and corn but now comes the big category the OTS or true dcot this group contains about 75% of all flowering plant species most of which only evolved relatively recently after the extinction of the dinosaurs utic cots are mostly split into either rosids or asterids but before we look at them let me point out a few exceptions two of the oldest UDOT families are the Lotus family and the Buttercup family which also includes poppies from which we get opium then there's the CIO feles order which includes all of the various types of cactuses as well as the famous venus fly trap one of the few examples of a carnivorous plant it also includes carnations and the amaroni family which contains spinach and beets okay let me now introduce you to rosids and asterids the two main categories of uots the terms come from the names of two famous flowers the rose and the aster or Daisy although take note that Aster literally means star that's because Asters look like stars not this kind but this kind which we call an asterisk now the really neat thing about Daisy like flowers such as the sunflower is that each flower is actually a constellation of many tiny little flowers even each petal is technically its own flower having evolved from multiple petals that fused together but the asteroid category contains more than just Fancy Flowers it also includes many plants that we eat and drink such as carrots coffee olives and the lamasi family which includes most herbs such as mint basil oregano and Thyme and then there's the Sola Nai family also known as nightshades which is ironic because Soul means Sun so is this a sun related family or a night related family well the origin of the term Nightshade is debated but one thought is that it's because some of the plants in this family are quite dangerous ranging from poisonous berries that can kill you immediately to Tobacco which if you smoke enough of it will kill you over time but it also includes many plants that are not dangerous like potatoes and tomatoes which brings me to the age-old question is a tomato a fruit or a vegetable well the answer may surprise you it's actually both from a botanist's point of view it's a fruit that's because it's a seed container that grows out of a flower however from a culinary point of view it's a vegetable that's because the word vegetable is actually an arbitrary term used for any part of a plant that is edible but not sweet so vegetables can be leaves like spinach stems like celery seeds like lentils flowers flers like broccoli Roots like carrots bulbs like onions or even fruit like tomatoes another part of certain plants that can be edible are tubers which are a part of the root system the most famous tuber is of course the potato so if you've ever wondered why potatoes and tomatoes can be so closely related yet look so different now you know why they are simply different parts of a plant let's now move over to the rosit there is actually no foolproof way to tell the difference between a rosid plant and an asteroid plant just by looking at them because the technical difference has to do with seed formation however generally speaking rosid plants usually have more obvious stipules which are those little things that stick out between a branch and a leaf stem unlike asterids rosids include both small plants as well as big ones AKA trees a tree is defined as any large plant with a central trunk we've already run across trees in the Conifer section but those were the Evergreen ones when it comes to deciduous trees meaning those that lose their leaves in the Autumn they are mostly found here among the rosids such as Elms Oaks Maples and Willows however rosids also include many edible plants such as squash beans grapes citrus fruits and cow which is used to make chocolate and then very closely related to the rose flower itself are apples as well as Peaches plums and all the various red berries now I should point out that when it comes to roses the ones you're likely familiar with don't actually occur in nature a Wild Rose like most uots only has five petals the many petal roses that people like to give to their lovers are the result of many many decades of human cultivation okay so that takes care of the plant kingdom for the rest of this video we're going to take a look at fungi for many centuries fungi were considered to be plants but we now know that they are actually more closely related to animals having split off from a common ancestor about 1 billion years ago the study of fungi is called micology from the Greek word Mikes meaning mushroom but there are a lot of other types of fungi Beyond just mushrooms a good example is bread mold which is considered a lower fungi if you let it grow you'll notice that it creates a huge network of tiny little threads these are called hyi and even mushrooms have them it's just that in that case they are usually underground it is the hyi that does what fungi are best known for decomposing organic material so for example if you let molds grow on an Apple the Apple will eventually disappear and you'll be left with a puddle of brown goop that's because the fungi will have basically eaten the Apple higher fungi can be divided into two main divisions bidio makota meaning club likee fungus and ASCO Mota meaning sacklike fungus ASCO Mota includes common molds as well as fungi that creates a symbiotic relationship with algae to create lyan however it also includes yeast both the type that causes infections as well as the type used to make bread it does this by eating the sugar in the flour creating gas that then causes the bread to rise another example of the fact that fungi can be either good or bad is these two closely related types again one type creates infections for humans such as ringworm and athletes foot but the other type is used to make the anti iotic penicillin remember fungi are good at eating or destroying things so in the case of penicillium what the fungi destroys is bad bacteria so we've just learned how to use this to our advantage under ASCO myota is also truffles besides mushrooms truffles are the other main type of fungi that humans eat however they are far more rare and thus usually quite expensive the final thing I want to mention in terms of Asco Kota is prototaxites I haven't included them on this chart but long long ago around the same time that the first vertebrates walked on land this giant fungus was actually the largest organism on land about as tall as a 3story building okay let's now look at Bido Mota and in particular the agaro mycedes class the word agaric is the technical term for any fungi that produces mushrooms in particular the kind with a rounded cap with gills underneath we tend to think of the mushroom part of an aaric as being its main part but in actual fact it's simply the equivalent of its fruit in other words a mushroom is the part of the fungus responsible for reproduction in this case by producing spores the main part of an agaric or any fungi for that matter is actually the network of hyi that I mentioned earlier which in this case is located underneath the mushroom the largest mushroom order is actually the poly Paralis order which includes all of the Shelf fungi that grow on the side of trees in contrast the main type of edible mushroom agaricus bisporus also known as button mushrooms belongs to the agara order which also includes shitake mushrooms psychedelic mushrooms and the super poisonous death capat mushroom but perhaps the most recognizable mushroom ter of all made famous by the Super Mario game is amonita muscarius known commonly as the fly agaric because it can be used to kill flies first off I need to address the word theory in everyday speech a theory is simply an idea that may or may not be true however in science that's not what a theory is at all for ideas that may or may not be true scientists use the word hypothesis instead and they reserve the word theory for ideas that have been tested over and over again and shown to be extremely reliable so take for example the theory of Helio centrism which is the idea that the Earth revolves around the Sun and not the other way around you probably assumed that this idea is now known to be a fact well it's not it's actually still just a Theory because no one has been able to travel far enough out into space to actually observe it happening however in science we don't ever say that something is just a theory because in science when something reaches the level of a theory it's basically as close to fact as you're going to get the other thing I want to clarify is what I mean by Evolution most creationists accept what they call microevolution which is an acknowledgement that species can and do change over time for example through human intervention large dogs can be bred to become smaller dogs and Wild Roses can be cultivated into complex hybrids and even without human intervention we know that white moths can eventually evolve to become black moths in order to better hide in their environment but this is not what I'm talking about what I'm talking about is what creationists call macro Evolution which is is when one species ends up evolving into a totally new species something which unfortunately we cannot directly observe because on average it takes more than a million years but it's even more than just macro Evolution what I also mean when I say evolution is the theory of common descent which is the idea that every single species on Earth can eventually be traced back to a single common ancestor now the opposite of the theory of evolution ution is the theory of creationism which is not just any belief in a Creator God but specifically the idea that God created each species on Earth at pretty much the exact same time and that all of those species have for the most part remained the same ever since so according to creationists fish were created at the same time as birds and mammals at the same time as insects so why am I so sure that creationism is wrong and that evolution is right well I'm going to give you six reasons starting with this one the older a geologic layer is the less diverse and less complex the fossils found within it will be you see over time changes occur to the Earth's surface and new layers of rock end up forming on top of older layers of rock this means that generally speaking the deeper down you dig the further back in time you go if creationism were true you'd expect to be able to find on average the same sorts of fossils wherever you look but this is not what we find for example Lions which according to Evolution appeared only recently are never found at deeper levels they're only found in more recent layers such as at the laa tarpits on the other hand fish which have been around for much longer are found both near the top as well as down in much deeper older layers of the earth it would take just one discovery of a fossil that goes against this pattern to disprove the entire theory of evolution so for example if any fossilized mammal were ever to be found at a very deep level where previously only Cambrian fossils had been found then boom the whole Theory would crumble but that has never happened because whenever fossils are found they always adhere to a very clear pattern lots of different types near the top including the most complex forms of life fewer and more simpler forms as you go down so if you were to chart out all of the 250,000 plus fossil species found to date according to how old each one is you'd end up with a chart that looked like well something like this okay reason number two all animals share the same basic anatomy even when it doesn't make sense to put it another way whether we're talking about reptile species bird species mammal species or even humans while each species may look very different each one is actually just a variation on the same basic body plan one that has four Limbs and a head with two ears two eyes two nostrils and just one mouth this indicates that all animals evolved from just one original species and then went in different directions from there you'd think that if a Creator had designed each species from scratch there'd be a bit more variety in terms of body plant like why no turtles with six legs or mammals with four eyes let's look at things in even more detail take for example our arms as I mentioned in episode two humans have a single bone in our upper arm called the humoris followed by two bones in our lower arm called the radius andna these are Then followed in our hands by carpal five metacarpal and five fanges well every single reptile bird and mammal even bats and whales have this exact same set of Bones just in different proportions again this indicates that we all evolved from just one original species that had this arrangement we can do the same sort of comparisons with insects and with plants and we can even combine all the various ancestor species together to get even older ancestor species in the end we'd end up with yet again something like this now before you argue well God just used designs for basic body plans that work really well and that's why we see them repeated well let me remind you of the second half of Point number two all animals share the same basic anatomy even when it doesn't make sense a good example of something not making sense is the lenial nerve which goes from the brain to the throat and is an aspect of the general animal body plan that we all share there's a bit of a design flaw in that the lenial nerve loops around the aortic Arch instead of going straight to the larynx which would have been easier for most animals this isn't much of a problem however for giraffes it creates a rather ridiculous scenario in which that nerve has to go all the way down the long neck loop around the arch and then go all the way back up again doesn't seem like something a designer would do but it does make sense if giraffe necks simply evolve to get longer over time an example in humans is our faulty sinuses if you want to learn more about them I suggest you check out this video by Stefan Milo which I'll link to in the description now all this talk of faulty design brings me to reason number three many animals have body parts that they no longer need take for example dolphins and whales unlike most mammals dolphins and whales have only two limbs they're fins instead of the usual four however if you look at their skeletons you'll find that they actually have bones for back limbs that they don't use in fact those bones are located entirely inside their bodies this is because once upon a time the ancestor of all dolphins and whales was a four-legged land creature but over thousands of years as that creature spent more and more time in the water it no longer needed its back limbs and therefore they just kind of whittel away even humans have features like this which are known as vestigial structures my favorite example is that of Goosebumps in most mammals Goosebumps serve the purpose of making an animal's hair stand up either when it's scared so that it looks bigger or when it's cold so that it can warm up humans still get goosebumps when they're scared or cold but because we no longer have much hair they no longer do anything except make our skin look like we've got a bunch of little pimples all right moving on one of the things that makes evolution so hard to accept is that it takes millions of years and therefore we can't see it happening in real time I mean even I'll admit the thought of a single cell evolving all the way to a human seems pretty crazy but here's the thing we can in fact see a single cell evolve into a human in just 9 months it happens every time a zygote grows to become a baby so let me now give you reason number four as fetuses grow they acquire features in the exact same order that they are predicted to have been acquired through Evolution the result is that at certain stages all animal fetuses look pretty much the same then they go in different directions just like they did in evolutionary history in order to better understand the significance of this imagine five different Lego sets all of which start out with the exact same set of instructions but then four of them get an additional set of instructions and one doesn't next Imagine That of the remaining four two get a third set called part 3A and the other two get part 3B finally imagine that those same four all get a fourth and final set of instructions but that this time each set is unique now if a Creator was designing five different Lego sets they could do it this way but they wouldn't have to if they wanted to they could simply make five different Lego sets all with different pieces and with different instructions so even if you believe that God created every species at the exact same time you can't deny that God did it in a way that made it seem like some species were designed off the plans of others as if God was experimenting which is weird because God is supposed to be perfect and therefore God shouldn't have to use trial and error so once again if we put all these step-by-step building stages for each species together and then sorted them out based on what built upon what well you guessed it it would look something like this so either evolution is true or God went out of the way and I mean really out of the way to make it look like evolution is true going as far as to make sure that only the fossils of really simple life forms ended up in the deepest layers of the earth okay for my last two points I'm going to get a bit more technical as you probably know the actual instructions for living things are stored in a structure called DNA well a single strand of DNA is called a chromosome and most animals have several chromosomes a full set of which is stored in every cell in their bodies the number of chromosomes a species has varies quite a bit from this ant which has just one to this butterfly which has about 450 but keep in mind that the number of chromosomes doesn't indicate how old a species is in terms of evolutionary history this is because chromosomes can both split and fuse and they do so often although by often I mean every few million years or so and and because they split and fuse so often and can do so in various different ways some chromosomes end up being really long and others end up being really short now how is this useful in terms of providing evidence for evolution well even though chromosomes can vary quite a bit you'd expect that two species that were very closely related would have very similar chromosomes both in terms of number and size so to test this let's take humans we have 46 chromosomes or two sets of 23 according to Evolution our closest ancestor is the chimpanzee so how many chromosomes do chimpanzees have well they have 48 or two sets of 24 as do gorillas and orangutans but let's Place one of their sets of 24 next to one of our sets of 23 take note that on this chart H stands for human and d stands for chimpanzee well what do you know most of the chromosomes match almost perfectly the only one that doesn't is our chromosome number two but in that case there are two chimpanzee chromosomes that when put together match it almost perfectly the most likely explanation for this is that our common ancestor like most great apes today had two sets of 24 chromosomes but then at some point in the branch that led to humans two chromosomes fused to become one reducing our total to two sets of 23 so my reason number five is just like a DNA test can determine who your closest human relatives are comparing broad similarities in DNA can determine who our closest animal relatives are now before I move on let me clear up a common misconception that people have about Evolution most people seem to think that Evolution says that humans evolve from chimpanzees but it doesn't what evolution says is that both humans and chimps evolved from a common ancestor one that was neither a human nor a chimp although I'll admit to the human eye that common ancestor looks more like a chimp than it does a human another thing that creationists like to say is if one species can evolve into another species take for example a tiger and an elephant how come we've never found a fossil of a half tiger half ele elant species again this boils down to a misunderstanding of how Evolution Works according to Evolution a tiger will never evolve into an elephant and an elephant will never evolve into a tiger however if we go back far enough in time we can find a common ancestor that was neither a tiger nor an elephant you see we can move forward along the branches of the evolutionary tree and we can even make new branches but one thing we can never do is jump from one branch to another or combine two branches to make a chimera okay my last Point Builds on point number five but gets even more technical it has to do with viruses viruses differ from living things in that they cannot survive on their own in order to replicate they need to infect a living host well sometimes a piece of a virus's DNA or RNA actually gets inserted into the host's DNA and then from there continues to get copied to f future Generations whenever this happens the new sequence is called an endogenous retrovirus or Erv usually the Erv doesn't cause any harm it's basically just the equivalent of the virus leaving a bit of graffiti saying I was here now don't start freaking out over the thought of a virus being able to change your DNA from the standpoint of a human lifespan Erv events are extremely rare but over hundreds of millions of years they do add up so much so that it is estimated that around 8% of the human genome is basically viral graffiti another way to look at it is to see these ervs as being sort of like fossils but in our DNA each one is a record of something that happened a very long time ago species that are closely related to us such as chimpanzees have virtually the exact same ervs as we do in the exact same places whereas species that are less related have less ervs in common again we can use ervs to map out the past and to find out which species are more related to which species and even build a tree based on our findings that will look one last time like this so reason number six is endogenous retroviruses serve as markers for when changes in DNA occurred and thus can be used to map out the tree of life so whether we chart out species by where their fossils are found or by how similar their body plans are or by how much DNA they share in common everything leads to the same conclusion there's a pattern to life on Earth that can be best described as looking like a tree in which from the top down each branch eventually merges with other branches which then merge with other branches and so on until we get to one single trunk going the other way from the bottom up life started small but over time mutations that turned out to be useful led to permanent changes in some species and as the process repeated itself not only did more and more species come to exist but more and more categories of species hence all the branches of the tree again I'll admit it's a pretty difficult thing to wrap one's mind around around but that's because our human brain did not evolve to think in terms of hundreds of millions of years logically we can understand what the number 100 million means but it's really hard for us to truly grasp just how long 100 million years really is and how given that much time how a sequence of tiny little changes can in fact add up to a massive amount of Change by the end now before I go I want to say two things first keep in mind that accepting Evolution does not mean giving up one's belief in God for some people it does but for many others it does not that's because accepting Evolution and believing in God can go hand in hand secondly understanding Evolution takes time if you're on the fence this one video is probably not going to be enough to convince you therefore I'm going to leave you with a few book recommendations that will help you explore further if you're going to read just one book it should be either why evolution is true by Jerry coin or The Greatest Show on Earth by Richard Dawkins both cover a lot of the same ground that I covered in this video but in much greater detail another great book is your inner fish by Neil shuin it demonstrates how our own bodies serve as a testament to all the various changes that have occurred throughout evolutionary history now for those of you who are religious and might be interested in reading something from an author who shares that in common with you I'll give two final recommendations finding Darwin's God by Kenneth Miller and life's solution inevitable humans in a lonely Universe by Simon Conway Morris thanks for watching [Music]